MHTML Generation and Loading
As implemented in Chrome
Authors: jianli@chromium.org
Last Updated: Nov 21, 2017
https://docs.google.com/document/d/1FvmYUC0S0BkdkR7wZsg0hLdKc_qjGnGahBwwa0CdnHE/edit#heading=h.s65c3k7eanp
Note: the long title line can be split into multiple lines using soft line break “CRLF+SPACE/TAB” per RFC 2047. The soft line break “=CRLF” used to break long line in message body as defined in RFC 2045 should NOT be used.

Unable to reproduce this isseu on reported version 63.0.3239.84 using Windows 10 with steps mentioned below.

1. Opened https://bugs.chromium.org/p/chromium/issues/detail?id=794835 >> From context menu selected save as and saved with extension mhtml
2. Added above mentioned text to saved html file, opened in browser and observed blank page.

@Reporter: Please provide sample URL to check this issue and also let us know where to check this issue. This would help in further triaging of this issue.

Thanks!

As example:
https://news.yandex.ru/

I believe this issue has relation to Blink>SavePage component but don`t know how to set it.

Comment 3 contain good sample URL. When I try to save https://news.yandex.ru/ to "WebPage, single file" the resulting mhtml file contain

Subject: =?utf-8?Q?=D0=AF=D0=BD=D0=B4=D0=B5=D0=BA=D1=81.=D0=9D=D0=BE=D0=B2=D0=BE=D1=81=D1=82=
=D0=B8: =D0=93=D0=BB=D0=B0=D0=B2=D0=BD=D1=8B=D0=B5 =D0=BD=D0=BE=D0=B2=D0=BE=
=D1=81=D1=82=D0=B8 =D1=81=D0=B5=D0=B3=D0=BE=D0=B4=D0=BD=D1=8F, =D1=81=D0=B0=
=D0=BC=D1=8B=D0=B5 =D1=81=D0=B2=D0=B5=D0=B6=D0=B8=D0=B5 =D0=B8 =D0=BF=D0=BE=
=D1=81=D0=BB=D0=B5=D0=B4=D0=BD=D0=B8=D0=B5 =D0=BD=D0=BE=D0=B2=D0=BE=D1=81=
=D1=82=D0=B8 =D0=A0=D0=BE=D1=81=D1=81=D0=B8=D0=B8 =D0=BE=D0=BD=D0=BB=D0=B0=
=D0=B9=D0=BD?=

Note: "WebPage, single file" can be enabled with chrome://flags/#save-page-as-mhtml

Thank you for providing more feedback. Adding requester "sc00335628@techmahindra.com" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

jianli@ - could you PTAL?  AFAIK the encoding was introduced in your https://chromium-review.googlesource.com/c/chromium/src/+/701262/4/third_party/WebKit/Source/platform/mhtml/MHTMLArchive.cpp

I am working on it.

Currently it seems to only affects using 3rd party MHTML parser to read a MHTML file saved by Chrome for those web pages with long subject. To help us evaluate the impact of this issue, which MHTML parser is affected?

Initially the problem was detected by user of FAR file manager. FAR has a plugin named Observer. This plugin allows user to extract objects (images, styles and so on) from mhtml files (and from any other mime files). Also 7Zip plugin eDecoder fails on such files.

In any case it will be better if Chrome (and all Chromium based browsers) creates correct mhtml files in accordance with RFC. All other browsers tested by me (old Opera, FF before 57 and IE) create mhtml files with RFC correct headers.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a97e4b274530e17656f7d493f4eb950502311e08

commit a97e4b274530e17656f7d493f4eb950502311e08
Author: Jian Li <jianli@chromium.org>
Date: Fri Jan 19 00:56:13 2018

Encode Subject header correctly per RFC 2047

Thee're some differences between RFC 2047 which we should be
used to encode header value and RFC 2045 for body:
1) Use CRLF+SPACE for soft line break.
2) SPACE and TAB should always be encoded.
3) Multiple encoded text should be used

Did manual test with FAR file manager w/ Observer plugin and
7-Zip w/ eDecoder plugin.

Bug:  794835 
Change-Id: I5b87b7392d2208dd58bf512c7ee59c87bc32a85a
Reviewed-on: https://chromium-review.googlesource.com/835009
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jian Li <jianli@chromium.org>
Cr-Commit-Position: refs/heads/master@{#530371}
[modify] https://crrev.com/a97e4b274530e17656f7d493f4eb950502311e08/third_party/WebKit/Source/core/frame/MHTMLTest.cpp
[add] https://crrev.com/a97e4b274530e17656f7d493f4eb950502311e08/third_party/WebKit/Source/core/testing/data/mhtml/soft_line_break.mht
[modify] https://crrev.com/a97e4b274530e17656f7d493f4eb950502311e08/third_party/WebKit/Source/platform/mhtml/MHTMLArchive.cpp
[modify] https://crrev.com/a97e4b274530e17656f7d493f4eb950502311e08/third_party/WebKit/Source/platform/text/QuotedPrintable.cpp
[modify] https://crrev.com/a97e4b274530e17656f7d493f4eb950502311e08/third_party/WebKit/Source/platform/text/QuotedPrintable.h

Tested this issue on Windows 10 on the latest Canary build 66.0.3330.0 by following the below steps.

1. Launched Chrome and enabled the flag #save-page-as-mhtml
2. Navigated to the page https://news.yandex.ru/ -> Save As -> file name: filename.mhtml and Save As type: Web Page, Single File.
3. On clicking on the .mhtml file, the page is invoking, but not sure where to check the Subject header encoding .
Attached is the screen cast for reference.

jianli@ Can you please check and confirm if anything is missed from our end in reproducing the issue.
Also please help us with where to check the Subject header is encoded correctly or no.

Thanks..

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I can confirm that 66.0.3330.0 creates correct mhtml files. If you open created mhtml file in Notepad you will see correct Subject header. Now it looks like this:

From: <Saved by Blink>
Snapshot-Content-Location: https://news.yandex.ru/...
Subject: =?utf-8?Q?=D0=9D=D0=BE=D0=B2=D0=B0=D0=BA=20=D0=BE=D0=B1=D1=81=D1=83=D0=B4?=
 =?utf-8?Q?=D0=B8=D0=BB=20=D1=81=20=D0=A8=D0=B5=D1=84=D1=87=D0=BE=D0=B2=D0?=
 =?utf-8?Q?=B8=D1=87=D0=B5=D0=BC=20=D0=BF=D0=BE=D1=81=D1=82=D0=B0=D0=B2=D0?=
 =?utf-8?Q?=BA=D0=B8=20=D1=80=D0=BE=D1=81=D1=81=D0=B8=D0=B9=D1=81=D0=BA=D0?=
 =?utf-8?Q?=BE=D0=B3=D0=BE=20=D0=B3=D0=B0=D0=B7=D0=B0=20=D0=B2=20=D0=95=D0?=
 =?utf-8?Q?=B2=D1=80=D0=BE=D0=BF=D1=83:=20=D0=AF=D0=BD=D0=B4=D0=B5=D0=BA?=
 =?utf-8?Q?=D1=81.=D0=9D=D0=BE=D0=B2=D0=BE=D1=81=D1=82=D0=B8?=
Date: Thu, 24 Jan 2018 16:49:38 -0000
MIME-Version: 1.0
Content-Type: multipart/related;
	type="text/html";
	boundary="----MultipartBoundary--SebsyQyHZ2k8hatblxDRVj7a0TP45ntfqebghJPQs2----"

Thanks.

Your change meets the bar and is auto-approved for M65. Please go ahead and merge the CL to branch 3325 manually. Please contact milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), bhthompson@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/bf03fcb2773f803f40f6ffce834677cce0af20d4

commit bf03fcb2773f803f40f6ffce834677cce0af20d4
Author: Jian Li <jianli@chromium.org>
Date: Wed Jan 24 22:11:05 2018

[M65 Merge] Encode Subject header correctly per RFC 2047

Thee're some differences between RFC 2047 which we should be
used to encode header value and RFC 2045 for body:
1) Use CRLF+SPACE for soft line break.
2) SPACE and TAB should always be encoded.
3) Multiple encoded text should be used

Did manual test with FAR file manager w/ Observer plugin and
7-Zip w/ eDecoder plugin.

TBR=jianli@chromium.org

(cherry picked from commit a97e4b274530e17656f7d493f4eb950502311e08)

Bug:  794835 
Change-Id: I5b87b7392d2208dd58bf512c7ee59c87bc32a85a
Reviewed-on: https://chromium-review.googlesource.com/835009
Reviewed-by: Xianzhu Wang <wangxianzhu@chromium.org>
Reviewed-by: Łukasz Anforowicz <lukasza@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Commit-Queue: Jian Li <jianli@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#530371}
Reviewed-on: https://chromium-review.googlesource.com/884512
Reviewed-by: Jian Li <jianli@chromium.org>
Cr-Commit-Position: refs/branch-heads/3325@{#73}
Cr-Branched-From: bc084a8b5afa3744a74927344e304c02ae54189f-refs/heads/master@{#530369}
[modify] https://crrev.com/bf03fcb2773f803f40f6ffce834677cce0af20d4/third_party/WebKit/Source/core/frame/MHTMLTest.cpp
[add] https://crrev.com/bf03fcb2773f803f40f6ffce834677cce0af20d4/third_party/WebKit/Source/core/testing/data/mhtml/soft_line_break.mht
[modify] https://crrev.com/bf03fcb2773f803f40f6ffce834677cce0af20d4/third_party/WebKit/Source/platform/mhtml/MHTMLArchive.cpp
[modify] https://crrev.com/bf03fcb2773f803f40f6ffce834677cce0af20d4/third_party/WebKit/Source/platform/text/QuotedPrintable.cpp
[modify] https://crrev.com/bf03fcb2773f803f40f6ffce834677cce0af20d4/third_party/WebKit/Source/platform/text/QuotedPrintable.h

Tested this issue on Windows 10 on the latest Chrome Build 65.0.3325.18 by following the steps mentioned in comment #12.

On saving the file as .mhtml file and opening the file in notepad, can observe the Subject header as mentioned in comment #13.
Attached is the screen cast for reference.

Hence adding TE verified labels as the fix is working as intended.

Thanks..

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